A long-acting ice pack includes a mixture of a cold preservation substance and a gel therein. The gel is mixed with a plurality of heat-insulating particles. For a portion of the ice pack, the heat-insulating particles can be used to block the transmission of the interior temperature of the ice pack and the outside temperature so as to decrease the area and efficiency of temperature transmission. The ice pack not only effectively extends the time of cold preservation, meeting the demand of ice compress or cold preservation for a long time, but also provides the most comfortable temperature for ice compress, without using a towel to cover the ice pack.